Knife's Edge
by Wild Rhov
Summary: Blindfolded, ears plugged, handcuffed, lost in a world of sensory deprivation, all Natsu can do is stay perfectly still as Gray's ice knife slides down his skin. It's a game of trust, and between the two teammate/rivals, trust means everything. Written for Kinktober 2019.


**Kintober 2019: Day 3** – Sensory Deprivation | Temperature Play | Edgeplay | Knife Play

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"Do you trust me?" Gray held an eye mask and magic earplugs that would block all sounds from even the sensitive ears of a Dragon Slayer.

Natsu sat naked on the edge of Gray's bed, his lips already swollen from making out for the past hour. Now they had moved things from the couch to the bedroom, but Natsu realized that Gray had a lot more planned for tonight.

"Yes," he answered, gazing straight into Gray's eyes.

With a relieved smile, Gray handed the earplugs over. As Natsu fitted them into his ears, all went completely silent. Then Gray pulled the eye mask on and adjusted it. He waved his hand in front of Natsu and even made a funny face, just to be certain he could not see. Then he leaned into Natsu's ear and bellowed.

"**_HEY, YOU STUPID JERK-FACE!_**" Not even a flinch.

For Natsu, the world had vanished. Without sight or sound, all he had to rely on was touch, taste, and his keen sense of smell. However, seconds later, a strong candle burned, so potent that Natsu felt like sneezing. It successfully ruined his sense of smell.

A hand touched his face, and he jolted in shock, only to relax, knowing it was Gray. Fingers tugged at his mouth, and he obediently opened it. Something large pressed between his teeth. A mouth guard? No, a gag, and he tasted the metal of a ring as it fit in his mouth, wrenching his jaws open. He could feel vibrations in his throat and chest of what he hoped were just soft moans, but the earplugs successfully blocked all sounds, even those he himself made.

As Gray leaned back and gazed at Natsu, there was one thing he loved best. Those moans! Whenever Natsu could not hear himself, he had no idea just how loud he got. With his mouth forced open with his tongue lolling through the O-ring, drawn outward by pure biology, every sound he made was exposed, from heavy panting, thick gulps, especially as the O-ring made him salivate profusely, and those delicious moans. Unable to hear himself, what Natsu thought was quiet was far louder than he got normally, and Gray craved it.

"You are so sinfully erotic," he whispered, knowing Natsu could not hear, so he could say all he wanted. Gray reached a finger through the O-ring and scratched the top of Natsu's tongue, making him jolt and yank back. "Mm, that's no good. I obviously have to keep you still."

He patted Natsu's wrists, and luckily his boyfriend knew precisely what to do. His wrists shot out, already together. "Ice Make: Handcuffs." The cuffs shimmered into existence around Natsu's wrists, and the freezing hardness made him groan, such a loud sound with his mouth forced wide open.

Gray shifted Natsu onto the bed, pulling him around to be on his knees, and trapped the handcuffs to the headboard. Natsu was left to rest on his elbows, his ass up in the air. Then he tapped Natsu's left ankle, a warning before forming an ice cuff around it. Again on the right ankle, a shimmering cuff, and then Gray formed a pole between the two, forcing Natsu's ankles far apart. He left to the bathroom and returned with a towel, placing it under Natsu, since he knew things were going to get messy. Then Gray stepped back to admire the sight.

"So vulnerable," he whispered in awe. His hand brushed down the vale of the spine, making Natsu's whole body arch at the feel. "You have no idea what I'm about to do to you. I could be planning anything, and you'd have to stay right there, trapped, bound by my ice. My prisoner."

He held up his hand. "Ice Make: Knife." It glistened in the dim light of the bedroom. "Seriously, I could stab you, and you'd never know it was coming. You're luck I love you too much to do that." He chuckled to himself and whispered into Natsu's ear. "I love you, but that doesn't mean I'm gonna go easy on you."

Lost in a world of darkness, Natsu felt like he was floating, yet trapped in oblivion. This was terrifying, yet he trusted Gray. He had to, now. An enemy could attack Magnolia and he would never know. Gray could be doing or saying anything, and he was trapped, so vulnerable, naked, bound, gagged, blind and deaf.

Just then, he felt ice. Of course, Gray would use ice in his sexy playtime. However, this ice was sharp. As it slid down his back, Natsu gasped. More than once, he had felt the tip of Erza's sword.

And that was precisely the same feeling now.

Was Gray sliding a _sword_ down his back? Was he planning to cut him?

Gray was being very careful, keeping an eye on Natsu's body and glad he was not squirming. The ice knife was super sharp, but Gray was an expert at wielding it, using weapons in fights so many times. The tip of the knife slid down Natsu's back, stopping just before his ass, not enough to cut, but enough to evoke just a little fear in Natsu. The heavy panting between the O-ring caught in a gasp.

"Gray!" Natsu tried to say, but with the gag it came out more like "Ghuah."

Gray kissed the side of Natsu's cheek to reassure him that he would take care of him. That was a silent signal to him, a way to calm him when he could not see or hear.

"You know, like this, I could do anything to you. I could bring someone else into this room to ravage you, and you wouldn't be able to smell them here. I could sit back and watch you be fucked by another man, and you'd never even know." He hummed with delight. "For today, I wanna listen to you until you go hoarse."

He reached under Natsu and wrapped his fingers around his cock. Natsu's hips were more than ready to hump in, but Gray placed the flat of the blade against his thigh, showing Natsu that he was not to move.

"I'll take care of everything."

He began to stroke, and a loud moan wailed out from the gaping mouth. As Gray stroked, Natsu shivered, until a clear drip of pre-cum formed on the slit of his cock. Right as he saw it, Gray pulled his hand away.

A wild growl of frustration roared through the gag, and there was even a little flame. _This_ was why Gray had to use the metal O-ring and not ice. Natsu's breath could melt an ice gag so fast, he would have to use his magic continually to replace it.

"Oh, you didn't like that, huh?" he taunted, patting the pink hair condescendingly. "I know how to cool you off."

He flipped the knife around. The pummel made a perfect butt plug, and he pressed it up into Natsu. The howl certainly could be heard from the street, and Gray even heard some prude shouting to keep it down.

"They can hear you. Oh, but you can't hear a thing, can you?" he mocked. Then he glanced down. "Look at that. A little cold, and you shrivel away."

He pulled the pummel out and replaced it with his tongue, hot and wet, making Natsu's body tremble. He heard a gag as Natsu almost choked on saliva, and he saw a long string of spit drooling down onto the towel.

"So messy." Gray walked over to his dresser, picked up a camera, and snapped a few pictures. He really wanted to show Natsu what he looked like, if only to further humiliate him. Satisfied with the erotic photos, he stroked Natsu again, and this time he rolled under, opened his mouth, and sucked on the hard cock. Immediately, Natsu lunged down, ready to ram into Gray's throat. He held the knife up, not stabbing enough to draw blood, but definitely enough to force Natsu to retreat.

"You have to stay there or else." He licked around the head, only that much, mere licks without sucking. The denial led to desperate cries. "You wanna thrust in, don't you? I can see you pushing on the knife. Don't think I won't let it cut you if you're bad."

He gave a full suck, and the loud moan reverberated through Gray's apartment. Natsu began to tremble again, and Gray pulled back. Natsu felt the knife leave his stomach, and he flopped down, gagging, moaning loudly into the pillows, garbled syllables of desperation.

"Do you really think I would let you end this that quickly?"

He wrapped around Natsu's cock again, stroking rapidly, roughly, until Natsu was almost starting to spasm, and then he pulled back again.

"Aaaaaaaaah!" All of Natsu's sexual frustration roared out, along with more flames. "Uck ee."

"Fuck me?" Gray laughed at the idea. "That's too easy." The knife slid down Natsu's spine again, only this time he flicked it, only a little, but enough. There was a pained cry, and blood beaded up on the skin. Then Gray pressed the ice knife on the wound, really driving in the pain, but he also knew this would keep the bleeding to a minimum. A few drops, maybe, and it would scab over. When he pulled the blade back, he saw blood on it.

"Man, if you could smell, you would love this. The scent of your own blood."

He dragged the knife further, along Natsu's ass, and to his thigh. Natsu hiccuped a sob of fear as the blade slid closer and closer to his groin.

"You know I'd never harm you there." He pulled back, but then he made a small nick right on Natsu's ass. There was a shout of pain, and Gray placed the flat of the blade on this wound as well. "You'll feel that when you sit."

He saw the blood on the blade, just a little redness on the ice, and Gray smirked to himself. He slightly changed the knife, dulling the edges and blunting the tip, to make it harmless. Then he brought it to Natsu's face. Gray put his palm on Natsu's forehead, forcing him to stay perfectly still, and slid the dull knife through the O-ring, slathering the blood onto Natsu's tongue.

"Taste it!"

The only things Natsu could experience were touch and taste. That blood on his tongue caught him by surprise, and he froze. However, instead of fear, Natsu's cock grew harder.

"Horny blood fetish," Gray muttered. "Let's try something."

The knife was not that long, but pressed into Natsu's mouth, it almost hit the back of his throat before reaching the handguard. Gray froze the knife to the metal O-ring and left it there, piercing Natsu's mouth, the taste of his own blood on it. It was dull, it would not slice up his mouth, but … Natsu didn't know it was dulled now. He began to whimper, trusting Gray but still afraid.

Gray patted Natsu's cheek again, reassuring him that he would be okay. Then Gray reached down and began to stroke the engorged cock again.

"You've been so good, I'll let you come. It's gonna scare you, though."

Sure enough, at the first moan, Natsu almost choked, realizing there was something in his mouth. He tried to cry Gray's name, but he could do nothing but try hard not to move his face, lest he slice his tongue off. He wanted to thrust into those fingers, but he feared moving too much. He seriously wanted to come, but the fear made him unable to for a while.

That allowed Gray to savor the feeling of Natsu hardening in his hand and dripping all over his fingers. Fearing an orgasm, he dripped profusely due to holding back. A sob shook out, but even that scared Natsu, as any movement of his mouth felt like it might stab the back of his throat.

"Oh, I like this. We need to do this more often."

Gray covered his finger in ice and slid it inside Natsu. The cry now was guttural, but still Natsu tried so desperately to stay perfectly still, not squirming as he normally did. The result was limbs that shivered and a growing tenseness through his whole body.

Gray was so turned on, he desperately reached down and began to stroke himself. He heard deeper, wilder grunts weighed down by the knife in Natsu's mouth. He thought about maybe fucking Natsu's ass, but before he could decide if that was a safe idea, Natsu's whole body jolted. Gray felt hot pulses in his hand as Natsu's cock burst out, splattering the towel under him.

Gray yanked the knife out of his mouth and instantly thrust his cock through the O-ring. Clutching Natsu's hair, he slammed in. Natsu had no choice but to be choked by that cock. He could not suck, could not move at all. He could only kneel there as his mouth was fucked. Then there was a new taste for Natsu to experience. The best taste of all.

The sexual delight of his lover!

It filled his mouth, pumping over his tongue, slithering down the back of his throat, and Natsu, unable to close his lips, even felt it sliding out of his mouth, dripping down his chin.

Gray shuddered as his body floated on a sea of bliss. "So good. You are so damn amazing."

He pulled back and saw Natsu, his mouth forced open, saliva and stringy white cum dribbling down his lower lip. Gray grabbed his hair and yanked his head up, so the cum dripped down his chin and over his throat.

"I need a picture." He grabbed the camera, and still holding Natsu by the hair, he snapped some shots of his mouth bathed in cum. "Shit, I love you so much!"

Gray moved slowly to get off the bed, and he put the camera away so Natsu would not guess he had taken pictures. He returned to Natsu, pulled the eye mask off, and saw him blink with wet eyelashes. Natsu looked gloriously fucked out of his mind.

"I love you," he said while Natsu still could not hear anything. After getting that off his chest, he pulled the earplugs out and set them aside. "Are you okay?"

In hazy bliss, Natsu nodded. Gray banished his magic, and the cuffs on his wrists and ankles disappeared. Then he carefully eased the ring out of Natsu's mouth. Gray wiped up the saliva with the messy towel, then rolled it up to be washed later. As he put the O-ring in a cup to be disinfected, Natsu worked out his stiff jaw.

"You asshole. You could've killed me."

"I asked if you trusted me." The knife was still on the nightstand, and Gray pulled it forth. Natsu saw that it was perfectly dull. He had a better chance of stabbing his throat with a spoon.

"Dammit, Gray," he grumbled. "You scared the hell out of me."

"Sorry."

Natsu wrapped his arms around him and snuggled in. "You have to make it up to me."

"Anything you want."

"A hot shower and a blowjob later."

"With _pleasure_." Gray laughed and hugged Natsu tightly to him. "You are the best boyfriend in the world. My beloved dragon!"

Gray heard a rumbling purr that let him know the Dragon Slayer might pout and whine, but he actually loved it too. That made Gray feel warm with delight.

**The End**

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_A/N: Long-time fans of my work... oh you BETTER BELIEVE we're gonna see this in FMBM. Although written for Kinktober, it's too perfect, and it was created with that dynamic in mind._


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